From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <SRS0+lY+I=O5=ericsson.com=mattias.ronnblom@lysator.liu.se> Received: from mail.lysator.liu.se (mail.lysator.liu.se [130.236.254.3]) by dpdk.org (Postfix) with ESMTP id 250381BAE5 for <dev@dpdk.org>; Thu, 20 Dec 2018 11:54:01 +0100 (CET) Received: from mail.lysator.liu.se (localhost [127.0.0.1]) by mail.lysator.liu.se (Postfix) with ESMTP id 973A540018 for <dev@dpdk.org>; Thu, 20 Dec 2018 11:54:00 +0100 (CET) Received: by mail.lysator.liu.se (Postfix, from userid 1004) id 8497040014; Thu, 20 Dec 2018 11:54:00 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on bernadotte.lysator.liu.se X-Spam-Level: X-Spam-Status: No, score=-0.9 required=5.0 tests=ALL_TRUSTED,AWL autolearn=disabled version=3.4.1 X-Spam-Score: -0.9 Received: from [192.168.1.59] (host-90-232-140-56.mobileonline.telia.com [90.232.140.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.lysator.liu.se (Postfix) with ESMTPSA id 3983340011; Thu, 20 Dec 2018 11:53:59 +0100 (CET) To: Thomas Monjalon <thomas@monjalon.net>, Jason Messer <jmesser@microsoft.com> Cc: dev@dpdk.org, Jeff Shaw <jeffrey.b.shaw@intel.com>, stephen@networkplumber.org, harini.ramakrishnan@microsoft.com References: <20181214163827.9403-1-jeffrey.b.shaw@intel.com> <20181214190713.GB9964@ae13-28.jf.intel.com> <3a573b56-6ea0-812c-4641-830fbd3c59cc@ericsson.com> <27594774.hr4jPcleJC@xps> From: =?UTF-8?Q?Mattias_R=c3=b6nnblom?= <mattias.ronnblom@ericsson.com> Message-ID: <be3930f2-3931-e9e8-4311-65479ffc5a9c@ericsson.com> Date: Thu, 20 Dec 2018 11:53:58 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <27594774.hr4jPcleJC@xps> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Virus-Scanned: ClamAV using ClamSMTP Subject: Re: [dpdk-dev] [PATCH] eal: remove variable length array X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <https://mails.dpdk.org/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://mails.dpdk.org/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <https://mails.dpdk.org/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Thu, 20 Dec 2018 10:54:01 -0000 On 2018-12-19 22:45, Thomas Monjalon wrote: > 14/12/2018 21:28, Mattias Rönnblom: >> On 2018-12-14 20:07, Jeff Shaw wrote: >>>>> The code prior to this commit produced the following warning when >>>>> compiled with "-Wvla -std=c90". >>>>> >>>>> warning: ISO C90 forbids variable length array ‘array’ [-Wvla] >>>>> >>>>> This commit removes the variable length array from the PMD debug >>>>> trace function by allocating memory dynamically on the stack using >>>>> alloca(). >>>> >>>> Is alloca() even included in *any* C standard? As far as I see, it just >>>> achieves the same thing in an uglier, less portable way than VLAs. >>> >>> I agree that it is much less elegant than a VLA. This is in preparation >>> for DPDK on Windows, which using the Microsoft Visual C++ (MSVC) compiler. >>> MSVC does not support variable length arrays. It does, however, support >>> alloca(), as does GCC/ICC. >>> >>> For this particular instance, the point is moot, since the function is >>> not used anywhere and can just as easily be removed. Though it does not >>> address the issue for the ~100 other instances where VLAs are used. We >>> will be submitting patches for those as more common files are ported to >>> Windows. >> >> If Microsoft's C compiler doesn't support C99, some 20 years after its >> release, maybe it's time to find a new compiler, instead of messing up >> the DPDK code in a ~100 instances. > > If think there is no reasonnable compiler for Windows. > Yes I know, it's crazy. > With's wrong with the Windows version of Clang?